I have the day off today with few to-do items, so I'm on the Jeep this morning and here's what I have found.
I decided to start with the carb fully closed. I went idle mix all the way in (closed), idle speed no contact, and secondary screw all the way out (closed).
It'll start and run with throttle, still showing some smoke and sputtering. When I'm off throttle, it'll idle down to about 500 then just slowly die after about 5 sec.
I started it again, keeping it running (about 800-1000rpm) then turned the idle mix screw from closed to about 1.5 turns out. It started running rougher and when I let off, it immediately dies.
Then I remembered I wanted to find where I start getting vac on the S port, so I decided to just get it to where it would idle and go from there.
I found that if I go idle mix closed, and secondary 2 turns in, it will keep running with the idle screw backed all the way off.
I put the vac gauge on the S port and found that I start getting vac on that port at 1 turn in on idle speed screw. That combo had me sitting at 1000 rpm and really idling rich.
After some fiddling around, I have found the best idle with the mix screw 1 turn out, idle speed 1 turn in (keeping it at 0 vac), and secondary 3/4 turn in.
It still idles rich and sputters, but not a constant flow of smoke, just puffs when it stumbles. But, when I step on the gas, there's quite a bit of constant smoke.
What do think my next step should be? Leaner jets? Call Weber and get a new carb? :-)
I adjusted the float to 18mm on Friday. It was 13mm...I posted that.
No I haven't changed plugs since last week before I started digging into this. I'll go get a fresh set, and a compression gauge and let you know what I find.
You have gone on the "extreme" figuring out and tuning the EMPI version, also made in China carburetor.
As you know, these "specs" that everyone has given are for a real Weber.
I say this as the progression holes drilled by the Chinese mfg's aren't always drilled the same height in the bore. Some too low, like yours seem to be and the throttle plates expose those holes. (running rich)
Drilled too high, and while you get a few hundred RPM higher idle speed you have a stumble off idle.
The float height at 18mm is for a Weber float, with F50 E-tubes works well, but a different buoyancy comes a different fuel height and the aux ventures come in sooner or later.
Typically the "S" port vacuum starts at ever so slightly more that 1 1/2 turns in on the speed screw, the position of the throttle plate is slightly exposing the enriching holes.
Not necessarily so with the Chinese copies.
Shawn suggested the idea of "cheating". This means closing the throttle plate below those enriching holes (your pics looked like two turns in on speed screw) and drilling a hole in the throttle plate.
Our joke is "Blasphemy" !! This hole drilling stuff is a very last resort to close the throttle plate up and yet have enough air volume to have a reasonable idle speed. (550 to 600RPM)
I have drilled 1/4" in from the leading edge of the throttle plate, The hole size was a spark plug gap, 0.040"...
Or, if you have had enough, I would recommend a real Weber 38-DGES, K551-38.
Yeah, sure did!! I was more curious where I would start picking up vac.
Ok, compression test:
Picked up another set of plugs but won't be able to get back to the Jeep for a couple hours.
I've been watching your efforts here and am reminded of my first "weber" experience. Bottom line: don't spend another dime on your carb -- buy a genuine Weber 38, set the throttle plates to spec, bolt it on and drive it like you stole it! Good luck! TrebleHook
1983 CJ8 Scrambler Laredo - 258 MOPAR MPFI/T-5/Dana 300 - 4.10 Dana 44 Rear/Dana 30 Front w/ ARB lockers front/rear - 4" BDS Suspension w/ Fox 2.0 Shocks - Ground Pounder Fab Front Shorty and Rear Spare Custom Bumpers - PSC Steering w/ Borgeson Shaft - 33x10.50 BFG KM2 on 15x8 Mickey Thompson Classic III - Work in progress.....
Matt, I'm waiting a call back from Redline. So, no, I don't want to fiddle with this carb
Unfortunately, that's probably your best bet. A genuine 38 is hard to beat. See if you can get him to install F-7 emulsion tubes and a viton needle and seat for you, assuming they even do custom assemblies.
__________________ Live in a way that those who know you but don't know God will come to know God because they know you.
Crap! Came out to garage after being gone 3 hours to find I left the ignition on from when I compression tested. Have I likely toasted something? The coil was disconnected from the dizzy. The coil temp is about 130*.
It's just one adventure followed by another :-(
Happen to have part numbers handy?
In the mean time, I'll have to start a new threat on my other discovery. Decided to start a swap on the valve cover gasket only to discover the front drivers side corner of it is broken along with other "mods". I was wondering where all that oil was coming from!